Decobalting oxo aldehyde product in the presence of liquid water



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MMM Clbborrze Patented May 25, 1954 Bacon-Amma oxo ALDEHYDE monocr- INTHEl PRESENCE OF LIQUID WATER.

John D. Koontz,k Baton Rouge, La., assiglnor to Standard- OilDevelopment ration. of Delaware Company, a corpo- Application November20, 1950,- Serial No. 1 96,3f1T 15 Claims. (Cl. 26o-604) Thisapplication is a continuation-impart' of* application Serial Number53,161, entitledCatalyst Removal in the filed October 7, 1948, nowabandoned.

The present invention relates to the preparation of organic compounds bythe reaction of carbonl monoxide and hydrogen with carbon com,- poundscontaining olenic linkages in the presence of a carbonylation catalyst.More specically, the present invention relates ery ofthe cobalt catalystutilizedin the foregoing reaQtion from the product of the thecobaltvcarbonylation reaction for further use inthe process.

Itis now Well known in the art that oxygenated organic compounds may besynthesized from organic compounds containing olenic linkages by areaction with carbon monoxide and hydrogen in` the presence of acatalyst containing metals of the iron group,such as cobalt or iron,prefer ably the former, in an essentially three-stage process. In thefirst stage, the olefinic material; catalyst and. the proper proportionsof @Gand-H2 are reacted to give a productl consistingpredominantly. ofaldehycles containing one more carbon atom than the reacted' olefin.This oxygenated organic mixture, which contains dissolved inits saltsand the carbonyls and molecular complexes of the metal catalyst, istreated in a second stage to cause removal of soluble metal compoundsfrom the organic material in a catalyst removal zone. The catalyst-freematerial is then generaliy liydrogenat-ed to the correspondingfalcohols,or may be oxidized tothe corresponding acid'.

Thiscarbonylation reaction provides a particularly attractive methodfor-preparing valuable primary alcohols which rind-large markets,particularly as intermediates for-plasticizers, detergents and solvents.Amenable to the reaction are long and short chained olelnicI compounds,depending-upon the type alcohols desired. Not only oleins, but mostorganic compounds possessing at least one non-aromatic carbon-carbondouble bond may be reacted by this method. Thus, straightand-branch-chained oleiinsand diolens such as propylene, butylene,pentene, hexene, heptene, butadiene,- pentadiene, styrene, olefinpolymers such as diand tri-isobutylene and hexene and heptene dimers,polypropylene, olenicfractions from the hydrocarbon synthesis process,thermal-or catalytic-cracking operations, and'other sources-ofhydrocarbon fractions-containing olens-may be used asistarting material,depending.- upon. thelnature of the iinal product desired-.fy

Carbonylation Reaction,

molecular fatty. acids., suchy as. stearic, oleic,. pal:

mitic, naphthenic, etc., acids.,` .'Ihus, suitabley catalysts are, forexample, cobaltcleate or naphthenate, or iron linoleate. 'Iheseysaltsare solublel 01?. H2159 CO, but pref.-

volumes. Ifhe Conditioneel reacting..definan/ith H2A and CO vary.Somewhat. inaccordance with.

but, the reaction is the nature of the olefin feed,

in` the range of. 'about i'aif k synthesis gasto. Qlieln fsedlma. Varywidely; in

seneraLabQut25Q0-tQ 1.50.0111 cubic. feet of H`2+CQ per barrelQfrolenlfeedare. employed It will be understcod' that. the Synthesisstasi previously referred to, i; .e., a ,y n containing primarily. andCO may be made by a plurality Qf. @gaven-tional" methods. For instanceitmay be. made bythe Water sas. reac-` tion, in other Wordaby reactinglcoke With Or, it maybe made by refo1mins 'meth ane or natural'g'as withvsteam, or. a mixture of Steam and'carbon dioxide- At the endoi the rststage; `when the desired conversion of olefins to qxygenated' compoundshas been, effectefth? PrQQllCU-lld. the lmeaQ/Cd. material are,generally Withdrawnto. a catalyst removal zone, Wheredissolved.,catalyst is removedfrom the mixture and it isy to. this stagethat the present principal' invention applies.

From the catalystremoval; zone the reaction products, comprisingessentially aldeh-ydes, may betransferredto a hydrogena-tion zone,andthe products reduced" to the corresponding alcohols in aina-nnerknown per` se. n

One of: theproblems involved in the aldehyde synthesis reactionis thefact that the catalyst metal, suchas cobalt; though addedas organicsalt, reacts with carbonmonoxide under the-synthesisconditions to formthe metal-r carbonyl; or hydro carbonyl; There isV basisfor the beliefthat the metal carbonyl' itselfis the active form of' the catalyst. Thisdissolved catalyst must be removedprior^ tothesubsequenthydrogenat-ion,as otherwiseitwould separate outV onthehyd-rogenation. catalyst, plugtransfer lines. and: heat exchangers,v etc. The carbonylremainsdissolved in.. the..- reaction. product; from; the primary bonylationstage and is, therefore. removed in the catalyst removal, or decobaltingzone. A good way to remove the cobalt is by a thermal method wherein theaccrued product in the first stage is heated to a temperature of fromabout 30W-,350 F.- Conveniently, a steam coil immersed in the liquid tobe decobalted is employed. A pressure of from about G-175 p. s. i. g. ismaintained in the decobalting zone by the injection of a gasiformmaterial such as hydrogen, an inert vapor, etc. It is desirable toemploy a gasiform material in order that the CO partial pressure bemaintained at a relatively low value in the decobalting zone.Periodically, it is necessary to take the decobalter off stream toremove accumulated metallic cobalt to prevent plugging of feed linesandadjacent areas of the decobalting vessel. Furthermore, cobalt metaldeposits as a nlm on the heating means and requires constant removal toprevent plugging of the preheating equipment and surfaces. The removalof these films and deposited cobalt metal is a tedious and difficultprocess and adds a significant cost to the economics of thecarbonylation reaction.

The purpose of the invention is to provide an efiicient means forreceiving cobalt in the catalyst decomposition zone.

Another purpose of the present invention is to provide a continuousmethod of decobalting the crude aldehyde product from the first stage ofthe process, which entirely avoids the older method of shutting downthedeccbalter to remove deposited cobalt by manual means.

Other and further objects and advantages of the invention will becomeapparent from the description hereinafter.

It has now been found that plugging may be substantially prevented inthe decobalting vessel and cobalt readily removed by a continuousprocess wherein the aldehyde product and dissolved catalyst withdrawnfrom the primary carbonylaat moderate pressures and somewhat elevatedtemperatures and discharged into the catalyst decomposition zone.Conditions of temperature and pressure are preferably adjusted tomaintain some water in the liquid phase. The live steam serves to heatthe aldehyde product to a temperature sufficient to decompose the cobaltcarbonyl and other metal complexes. The mixture is then cooled, gasesremoved overhead, and the material is conveyed to a separator. The upperaldehyde layer is withdrawn, passed if desired, through a filter toremove any suspended or dispersed cobalt, then passed to thehydrogenation zone. 1n like manner, the lower aqueous layer may bepassed through suitable lters and cobalt recovered. The recovered cobaltmay, if desired, be reconverted into catalyst by a manner known per se.

The present invention and its application will best be understood fromthe more detailed description hereinafter, wherein reference will bemade to the accompanying drawing, which is a schematic representation ofa system suitable for carrying out a preferred embodiment of theinvention.

Referring now to the diagram, an olefinic hydrocarbon having one carbonatom less than the number of carbon atoms in the desired resultingoxygenated compound, preferably alkali washed prior to reaction, andpreheated in a red coil (not shown), is fed through feed line 4 to thebottom portion of primary reactor 2. The latter comprises a reactionvessel which may, if desired, be packed with non-catalytic material,such 4 as Raschig rings, porcelain chips, pumice, and the like. Reactor2 may be divided into discrete packed zones, or it may comprise but asingle packed zone, or even, if desired, may contain no packing.

The olennic feed contains dissolved therein O.l-0.5% by weight of cobaltbased on the olefin. Compounds of cobalt or iron or their mixtures maybe employed. Cobalt oleate or naphthenate is preferably used.Simultaneously a gas mixture comprising H2 and CO in the approximateratio of 0.5 to 2 volumes of H2 per volume of CO is supplied throughline 6 to primary reactor 2 and flows concurently through reactor 2 withsaid olen feed. This gaseous mixture of H2 and CO is preheated with theolefin in the fired coil to virtually reaction tempera- CO gaseousmixture may, however, bypass the fired coil. Just prior to introductionof the feed into the reactor 2, the catalyst is injected into the feedstream. Reactor 2 is preferably operated at a pressure of about250G-3500 p. s. i. g. and at a temperature of about 250-450 F.,depending upon the olen feed and other reaction conditions. The rate offlow of synthesis gases and olen through reactor 2 is so regulated thatthe desired conversion level of the olefin is obtained.

Liquid oxygenated reaction products containing catalyst in solution, andunreacted synthesis gases are withdrawn overhead from an upper portionof high pressure reactor 2 and are transferred through line 3conventional means of cooling are employed, and from thence via line I2to high pressure separator It'. where unreacted gases are withdrawnoverhead through line IG, scrubbed in scrubber I8 of entrained liquidand cobalt carbonyl and used in any way desired. rJIhey may be recycledto synthesis gas feed line 6 via line 2G and booster compressor 23, orpurged via line I9.

A stream of primary reaction product containing dissolved therein arelatively high concentration of cobalt carbonyl and/or hydrocarbonyl iswithdrawn from separator I4 through line 22. A portion of said withdrawnstream may be recycled, if desired, to reactor 2 via line 214 to aid inthe cooling and maintenance of temperature control of the primarycarbonylation stage. The balance of the primary reaction product may bewithdrawn through pressure release valve 26 and through line 28. Thewithdrawn liquid may comprise any unreacted olefin as well as aldehydes,secondary reaction products, and dissovled catalyst compounds. Thisliquid is passed through line 28 todecobalter 3B. Also charged to thefirst of two decobalter towers 30 (one shown) is water or live steamadmitted through pump 3I and line 92. Steam may be injected into thedecobalter at the system pressure of from about 0-500 p. s. i. g.,preferably in the range of from about 50-200 p. s. i. g. and superheatedto a temperature in the range of from about 212-400 F. Conditions oftemperature and pressure are preferably adjusted to maintain some waterin the liquid phase. Decobalter 36 may be heated by heating coil 5I.Within decobalter 30 cobalt carbonyl is substantially decomposed and thestreams of carbonylation product, steam and water containing soluble andinsoluble decomposed catalyst is passed through line SII to soaker 38where part of the remaining steam is allowed to condense. Gasiformmaterial, such as CO resulting from the decomposition of the cobaltcarbonyl, and remaining uncondensed steam are withdrawn overhead tocooler I0 in which any 4 from 38- through line 36. In soaker 38 thematerial is allowed to stratify into two liquid layers, namely, an upperlayer comprising mainly carbonylation product and other organicmaterial, and a lower aqueous layer, wherein the bull: of thecobaltappears in both soluble and insoluble form. The upper layer iswithdrawn from 3B through riser itl and line 152 and passed into settlerde. Carbonylation product now substantially free of cobalt is withdrawnfrom settler 44 by line li-S and pump $8 and passed through filter 50and line 52 to the hydrogenation stage as indicated above. Any aqueouslayer in settler t4 is withdrawn through line 54 for recovery ofcatalyst contained therein.

The lower aqueous'layer in soaker 38 is withdrawn through line 4I. Thisstream contains the bulk ofthe decomposed catalyst and it may berecycled as a catalyst stream back to the 0X0 stagethrough line It orthe decomposed catalyst may be recovered for reuse in its original form.

The invention admits of numerous modications apparent to those skilledin the art. Thus, mention has not been made of various accessoryequipment which normally would be used in a commercial plant. Thus, inthe interest of good heat economy, various heat exchangers andeconomlzers would be employed to utilize whatever hea-t is available inthe most efficient manner, and in order to control the process, pumps,compressors, vValves, flow meters, etc. would be included in theeuuipment. If desired, either or both the upper and lower layers in zone46 may be passed to a settling zone, where suspended cobalt material maybe allowed to settle out prior to filtering. Aiso, instead of steam,water under suitabe conditions of temperature and pressure may beemployed in the decobalting step. Decobalter 39 may comprise two towers,operated in series or alternately.

To illustrate further the excellent results obtained by this inexpensiveand effective method for removing catalyst from the primarycarbonylation reaction product, steam at 340 F. was injected at 125pounds pressure into a closed twoliter bomb containing one liter ofwater and 500 cc. of primary carbonylation reaction product resultingfrom carbonylation of a C7 olein. After the pressure in the bomb reachedthat of the steam, one liter of water was drained from the 5 bottom ofthe bomb over a period of a half hour, the bomb being maintained under apressure of 125 pounds during this interval. The bomb was then cooledand the product withdrawn. AA

centrifuged sample of this resulting product contained 0.004% cobalt ascompared to 0.113% co' balt in the sample before steam treating.

A more complete removal of cobalt in the decobalting step may beachieved by adding water (or steam) in amounts from 2% up to 50% byvolume 0i.`- the oxo or first stage product and carrying out thedecobalting at temperature in the range of about 250-5c0 F., whilemaintaining a pressure of from about 50-175 lbs. per sq. inch on thedecobalting system. These severe decobalting conditions just nowdescribed have been shown, in a commercial unit, to remove over 99% ofthe cobalt dissolved in the crude aldehyde as it is recovered from theiirst stage of the process. rEhe recovered cobalt may be in the form ofcobalt metal, cobalt formate or basic cobalt formate. Formic acid isprobably synthesized during the rst stage of the process, or it may beformed from the oleic, naphthenic or other acid radicals associated withthe cobalt to the first stage of the process .to produce for-mate orAbasic'cobalt formate. In any event, formi'c acid apparently reacts with.the cobalt, in the presence of the added water, .to produce the cobaltformate or basic formate. The thus recovered cobalt or basic cobaltformate may be recycled totherst stage of the process in solution orsuspension, formed into a paste and injected into the oxo stage bypiston displacement, or converted to a more suitable catalyst.

Another important variable in good decobalting is that of residencetime. In other Words, in order to permit reaction between the cobaltmaterial and the formie acid (produced by hydrolysis 'of esters presentin. the first stage, by synthesis from reactants in first stage, etc.) atime period tof about `2 hours is required Where the conditions are asfollows:

Temperature 300-350F.

Pressure 10G-200 p. s. i. g.

Per cent water in l-25% (by volume), prefliquid phase erably 5-20%Residence time 2 hrs. (e. g. in a soaking drum not shown in drawing).

There is listed in the following table the results of five tests whichshow 'that the present invention of water injection into the decobalteris superior to the older thermal method described previously. .In testNo. 1 the older thermal decobalting method was employed, while in testNos. 2-5 varying amounts of water in the liquid phase existed in thedecobaltingI zone as shown in the data appearing in the table. As thesedata show, maintaining 16 voiume per cent water in the .liquid phasepermitted as satisfactory decobalting as` the maintenance of the higheramounts of 43-and '76 volume per cent water in the liquid phase.

Table Test N o.; 1 2 8 4 5 Water injection, Vol. percent 0 21/2 5 10Water in liquid phase, Vol.

percent 1 0 16 43 76 7 Decobalter Temperature, F.:

First Tower 330 340 340 340 200 Second Tower.- 350 Soaker 325 315 315315 260 Decobalter pressure, p. s. iA g 10U-150 175 175 175 100 CobaltAnalysis: Product,

p. p. In? soluble l Based on water injected.

2 Parts per million of cobalt material remaining dissolved afterdecobaltiug treatment.

In the foregoing test, as previously indicated, test No. l was carriedout employing the older thermal decobalting method with the towersoperating in series. In test No. 2 cobalt metal, cobalt formate andbasic cobalt formate sepa the soaker contained dissolved cobalt formateplus free formic acid. In test No. 3 no basic cobalt was formed, butotherwise the same results were secured here as were secured in test No.2. In test No. 4 the same results were obtained as obtained in test No.3, namely, they kwere the same as obtained in test No. 2 except forAnother feature of the present invention involves degassing the crudealdehyde product prior to the water injection. This may be accomplishedby reducing pressure. Degassing has the effect of reducing corrosion ofthe gas phase equipment caused by formic acid (or other acidicmaterial), present in the aldehyde product.

Numerous modifications of the invention may be made by those familiarwith the art.

What is claimed is:

1. In a carbonylation process wherein carbon compounds containing olenicdouble bonds are contacted in an initial reaction zone with carbonmonoxide and hydrogen in the presence of a cobalt carbonylation catalystunder conditions to produce reaction products comprising oxygenatedorganic compounds containing at least one more carbon atom than saidcarbon compounds and wherein cobalt carbonyl is dissolved in saidreaction products, and the solution comprising said reaction productsand the therein dissolved cobalt carbonyl is transferred to a catalystremoval zone, the improvement which comprises injecting a fluid selectedfrom the class ot live steam and water in said solution, maintaining atemperature oi the mixture of from about 200-500 F. in said catalystremoval zone, maintaining a liquid water phase in said racne, andmaintaining a contact time of said reactants for a period suiicient tocause a hydrolytic reaction.

2. The process of claim 1 wherein the system is under a pressure in therange of about -500 p. s. 1. g.

3. The process of claim 1 where the system is under a pressure of about50-200 p. s. i. g.

4. In a carbonylation process wherein oleiinic carbon compounds arecontacted in an initial reaction zone with carbon monoxide and hydrogenin the presence of a cobalt carbonylation catalyst under conditions toproduce reaction products comprising oxygenated organic compoundscontaining at least one more carbon atom than said olefinic compoundsand wherein cobalt carbonyl is dissolved in said reaction products, andthe solution comprising said reaction products and the therein dissolvedcarbonyl transerred to a catalyst removal zone, the improvement whichcomprises injecting live steam at a temperature from about 212 to about400 F. into said catalyst removal zone in contact with said solution,heating said solution by the sensible heat of said steam, and the heatreleased by condensation of said steam, maintaining a residence time oisaid reactants for a period sufcient to cause a hydrolytic reaction,maintaining a liquid water phase in said Zone whereby said cobaltcarbonyl is decomposed into products comprising metallic cobalt, cobaltformate and basic cobalt formate maintaining said solids substantiallysuspended in said mixture of steam, water and carbonylation product,transferring a mixture comprising said steam, water, carbonylationproduct, and suspended solids to a cooling zone, condensing said steam,passing a mixture of carbonylation product, condensed steam andsuspended decomposed catalyst to a quiescent zone, and separating anupper layer comprising said carbonylation product from said zone.

5. The process o claim 4 wherein said upper layer is sent to a settlingZone prior to passage through a filtration zone.

6. The process ci claim 5 wherein said upper layer is sent to a ltrationZone and an aldehyde product substantially free of catalytic material isrecovered.

"1. The process of claim 6 wherein said filtered product is sent to ahydrogenation zone.

8. The process of claim e wherein a lower aqueous layer containingsuspended decomposed catalytic material is withdrawn from said quiescentzone, passed to a filtration Zone, and recovered catalytic material isre-employed to furnish at least a portion of the catalytic requirementso the system.

9. In a carbonylation process wherein carbon compounds containing olenicdouble bonds are contacted in an initial reaction zone with carbonmonoxide and hydrogen in the presence of a cobalt carbonylation catalystunder conditions to produce product comprising oxygenated organiccompounds containing at least one more carbon atom than said first namedcarbon compounds and wherein cobalt carbonylation catalyst is dissolvedin said reaction products, and the solution comprising said reactionproducts and the therein dissolved cobalt carbonyl is transferred to acatalyst removal zone, the improvement which comprises injecting waterfrom an external source into said last named zone, maintaining atemperature of from about 200-500" F. in said zone and maintaining apressure in said zone such that at least a portion of the water in saidzone is in the liquid phase, maintaining a residence time of saidreactants Jfor a period suillcient to hydrolize at least a portion ofthe hydrolyzable components of said reaction products, withdrawing analdehyde product substantially free of dissolved cobalt from said Zone,and withdrawing cobalt-containing water from said zone.

l0. The process of claim 9 wherein said pressure is about -200 pounds.

1l. The process of claim 9 wherein the amount of water added to saidcatalyst removal zone is about 2-50% by volume o said oxygenated productpassed to said zone.

12. The process of claim 9 wherein 1-25% of said water injected intosaid last named zone is maintained in the liquid state in said zone.

13. The process of claim 9 wherein the residence time cf said reactantsis maintained long enough to hydrolize at least a portion of the esterscomprising said oxygenated product Withdrawn from said initial zone.

14. The process of claim 9 wherein at least a portion of saidcobalt-containing water recovered from said catalyst removal zone ispassed to said initial reaction zone to provide a portion of thecatalytic requirements of said zone.

15. The process of claim 9 wherein said oxgygenated product, prior topassage to said catalyst removal Zone, is degassed.

References Cited in the file of this patent UNITED STATES PATENTS

1. IN A CARBONYLATION PROCESS WHEREIN CARBON COMPOUNDS CONTAININGOLEFINIC DOUBLE BONDS ARE CONTACTED IN AN INITIAL REACTION ZONE WITHCARBON MONOXIDE AND HYDROGEN IN THE PRESENCE OF A COBALT CARBONYLATIONCATALYST UNDER CONDITIONS TO PRODUCE REACTION PRODUCTS COMPRISINGOXYGENATED ORGANIC COMPOUNDS CONTAINING AT LEAST ONE MORE CARBON ATOMTHAN SAID CARBON COMPOUNDS AND WHEREIN COBALT CARBONYL IS DISSOLVED INSAID REACTION PRODUCTS, AND THE SOLUTION COMPRISING SAID REACTIONPRODUCTS AND THE THEREIN DISSOLVED COBALT CARBONYL IS TRANSFERRED TO ACATALYST REMOVAL ZONE, THE IMPROVEMENT WHICH COMPRISES INJECTING A FLUIDSELECTED FROM THE CLASS OF LIVE STEAM AND WATER IN SAID SOLUTION,MAINTAINING A TEMPERATURE OF THE MIXTURE OF FROM ABOUT 200*-500